Knock-down quarter pipe for skateboarders, bikers and in-line skaters

ABSTRACT

A knock-down quarter pipe for bikers, skateboarders and in-line skaters has a base, and a plurality of legs extending up from the base, the legs having lower ends lying in a common plane. A deck is supported by the legs at a selected elevation above the base, the deck having front and rear edges and a surface extending between those edges that is substantially parallel to the plane. A ramp extends from the front edge of the deck down to the plane, that ramp having a lower leading edge that is located in that plane and spaced in front of a base. Preferably, the base and at least the lower end portion of the ramp may be filed with a fluid medium to add weight to and lower the center of gravity of the quarter pipe. Preferably also, a rigid coping rail is located between the front edge of the deck and the ramp which can function as a grind rail.

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application is a continuation of Ser. No. 10/282,848, filedOct. 29, 2002, now Patent ______.

BACKGROUND OF THE INVENTION

[0002] This invention relates to obstacles used by skateboarders, bikersand in-line skaters to enhance their individual ability and enjoyment.It relates more particularly to an obstacle referred to as a quarterpipe.

[0003] 1. Field of the Invention

[0004] A quarter pipe, as the name suggests, is an obstruction which hasa shape corresponding to one quadrant of a cylinder with an entry edgeof the cylinder being located next to the ground. The quarter pipe thusconstitutes a ramp which redirects a rider entering the ramp upwardapproximately 90° to a platform, cornice or rail which allows the riderto reverse direction and roll down the quarter pipe to ground level.

[0005] Usually such quarter pipes are relatively massive unitaryobstacles made of reinforced concrete or the like and because of theircost, they are usually only found in parks and other public spaces. Theyare not designed for home use.

SUMMARY OF THE INVENTION

[0006] It is an object of the present invention to provide a quarterpipe which can be sold in a knock-down condition and assembled by theaverage purchaser for home use.

[0007] Another object of the invention is to provide such a quarter pipewhich is easy to assemble and, when assembled, is rugged enough towithstand prolonged use by skateboarders, bikers and in-line skaters.

[0008] A further object of the invention is to provide a quarter pipewhich, although portable, is quite stable in use.

[0009] Yet another object of the invention is to provide a knock-downquarter pipe composed of a minimum number of parts which can beassembled in a minimum amount of time without requiring any tools.

[0010] Other objects of the invention will, in part, be obvious andwill, in part, appear hereinafter.

[0011] The invention accordingly comprises the features of construction,combination of elements and arrangement of parts which will beexemplified in the following detailed description and the scope of theinvention will be indicated in the claims.

[0012] Briefly, our quarter pipe comprises a base supported by aplurality of legs which extend up to a raised platform or deck. A curvedramp extends from an edge of the deck down to the ground in front of thebase, the ramp being composed of a wedge-like entry section adjacent tothe ground and one or more concavely curved ramp sections which extendfrom the entry section up to the deck. Preferably, the upper end of theramp sections transition to the deck by way of a coping rail which mayfunction as a grind rail for skateboarders and skaters using the quarterpipe. Preferably also, a handrail extends up from the rear edge of thedeck opposite the ramp sections as a safety precaution. Also, in apreferred embodiment of the invention, the aforesaid base and entrysections are designed to be filled with a relatively heavy fluid mediumsuch as water or sand in order to increase the weight of the apparatusand lower its center of gravity. This helps to stabilize the quarterpipe and prevent it from moving around when in use.

[0013] As we shall see, the quarter pipe is composed of a minimum numberof parts which are relatively inexpensive to make in quantity and whichcan be assembled very easily using only a screwdriver when the unit isfirst set up and no tools thereafter. Therefor, it can be sold in aknock-down condition for assembly by the purchaser. Furthermore, whennot in use, it can be disassembled without any tools and stored in aminimum amount of space. Therefor it should prove to be a popular andmarketable toy product.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] For a fuller understanding of the nature and objects of theinvention, reference should be made to the following detaileddescription taken in connection with the accompanying drawings, inwhich:

[0015]FIG. 1 is a right front perspective view of a quarter pipeincorporating invention;

[0016]FIG. 2 is a rear elevational view thereof;

[0017]FIG. 3 is an exploded perspective view, with parts broken away,showing the components of the FIG. 1 quarter pipe in greater detail;

[0018]FIG. 4 is a sectional view taken along line 4-4 of FIG. 1;

[0019]FIG. 4A is a similar view showing the same parts disassembled;

[0020]FIG. 5 is a sectional view, on a larger scale, taken along line5-5 of FIG. 1, and

[0021]FIG. 5A is a sectional view taken along line 5A-5A of FIG. 5.

DETAILED DESCRIPTION OF AN ILLUSTRATIVE EMBODIMENT

[0022] Referring to FIGS. 1 and 2 of the drawings, our quarter pipe,shown generally at 8, comprises a generally rectangular base 10 in theform of a water tank having a rear wall 10 a and a front wall 10 b. Thebase is supported at its corners by a pair of tubular rear legs 12 and apair of tubular front legs 14. Those legs extend up to a generallyrectangular raised deck or platform 16 which is spaced appreciably abovebase 10 and has a rear wall 16 a, a front wall 16 b and opposite endwalls 16 c and 16 d. As best seen in FIG. 2, the front legs 14 are moreor less vertical, while the rear legs 12 are toed in so that they may beslightly longer than legs 14 in order to maintain deck 16 in ahorizontal plane.

[0023] As shown in FIG. 1, an inverted, generally U-shaped tubularhandrail 18 extends up from deck 16 adjacent the rear wall 16 a thereof.Preferably, the legs of the handrail 18 are aligned with rear legs 12.Preferably also, the handrail is composed of two mirror-image L-shapedsections 18 a, 18 a connected at their upper ends by a short tube 19telescoped into the opposing ends of the two sections. The sections maybe clamped together around the tube 19 by a clip 20 of the typedescribed in application U.S. Pat. No. 6,547,221, the contents of whichare hereby incorporated by reference herein.

[0024] Still referring to FIGS. 1 and 2, deck 16 supports at its frontedge 16 b the upper end of a ramp shown generally at 22. The ramp hasconcave curvature so that its lower end rests on the ground well infront of base 10. As best seen in FIG. 1, ramp 22 is preferably composedof at least two identical arcuate ramp sections 22 a, 22 a arranged sideby side, and a generally wedge-shaped entry section 22 b which supportsthe lower ends of sections 22 a and extends down to the ground so thatthe totality forms a concavely curved ramp surface which presents asharp leading edge at ground level.

[0025] Preferably also, the transition of the upper end of ramp 22 todeck 16 is provided by means of a generally horizontal, rigid, tubularcoping rail 24 which extends the full width of ramp 22 and may befunction as a grind rail. The diameter of the coping rail is such thatthe opposing ends of the deck and ramp upper surfaces are tangent to thecoping rail. This enables a skateboarder, for example, while rolling upramp 22 to deck 16 to pause on, or roll along, rail 24 in order toreverse direction and roll down ramp 22 to the ground. On the otherhand, a rider riding up ramp 22 may roll over the coping rail 22 ontodeck 16 in order to rest or execute a reversal on the deck. The handrail18 is provided to assist in that respect and for safety reasons. Also toprevent overtravel of skate wheels, a raised rib 25 may be providedadjacent the rear wall 16 a of the deck, the rib extending at leastbetween the legs of handrail 18.

[0026] As we shall see, the components of the quarter pipe aredimensioned and spaced so that when assembled, the apparatus is quitestable while in use. To add to this stability, the base 10 and entrysection 22 b are preferably weighted to increase the overall mass of theapparatus and to lower its center of gravity. This assures that when arider rolls up ramp 22 to deck 16, the weight and momentum of the riderwill not cause the apparatus to tip over, tilt or shift relative to theground.

[0027] As shown in FIGS. 1 and 2, the illustrated base 10 is generallyrectangular and molded of a suitable strong, weather-resistant plasticsuch as polyethylene. Typically its dimensions are 4 ft. by 2 ft. by 4in. Preferably, the base is solid or rigidified at the corners so thatthrough holes 32 may be provided to accommodate the legs 12 and 14.However, the remainder of the base 10 is preferably hollow to provide afluid tight cavity 34 which may be filled with a fluid such as water orsand in order to increase the weight of the base. As best seen in FIG.1, one or more holes 36 may be provided in the top wall 10 a of base 10adjacent to the center line thereof to fill up, and drain the fluidfrom, cavity 34. When the base is filled with fluid, these holes may beclosed by suitable plugs 38.

[0028] When assembling legs 12 and 14 to base 10, the lower ends of thelegs are inserted through the comer holes 32 in the base and end caps 40are secured to the lower ends of the legs so that the comers of the baseare supported by the end caps when the end caps rest on the ground orother support surface. Alternatively, the base 10 itself may rest on theground.

[0029] Referring to FIGS. 1 to 3, deck 16 is also a generallyrectangular molded plastic article having dimensions slightly smallerthan those of base 10. Typically, the deck 16 is spaced about 3 feetabove the ground. However unlike base 10, deck 16 is not hollow. Ratherit has an open bottom and a multiplicity of intersecting ribs 42 extenddown from the top wall of the deck between the side and end wallsthereof to form a grid structure which makes the deck quite resistant tobending and racking forces.

[0030] As best seen in FIG. 2, a pair of vertical through holes 44 areprovided in deck 16 adjacent to the rear comers thereof directly abovethe upper ends of rear legs 12. These holes are smaller than the leg 12outside diameter but are large enough to slidebly receive the lower endsof the hand rail sections 18 a which are sized to telescope into theupper ends of legs 12 as shown. The hand rail sections 18 a may bereleasably retained in legs 12 by conventional spring-loaded pushbuttons 46 mounted in the legs of sections 18 a and which snap intoholes 47 formed in legs 12. The deck 16 is supported by rigid washers 49which sit on the upper ends of legs 12 as shown in FIG. 2, the openingsin the washers being sized to slidebly receive the legs of the railsections 18 a.

[0031] The attachment of the front legs 14 to deck 16 is somewhatdifferent as will be described shortly. Also for reasons that willbecome apparent, deck 16 is provided at one side with a long key or alug 48 which projects out laterally from the deck and has an upwardlyextending nose 48 a. In addition, an elongated keyhole or notch 50 isprovided at the opposite end of deck 16 which is adapted to receive thekey 48 of an adjacent deck 16. This allows the FIG. 1 quarter pipe 8 tobe keyed to one or more adjacent similar quarter pipes 8 arranged sideby side as shown in phantom in FIG. 1.

[0032] Referring to FIG.3, the front edge 16 b of deck 16 is formed witha pair of aligned notches 52 spaced apart along that edge and separatedby a relatively long shelf 54 which projects out from deck wall 16 b.The shelf 54 has an upper surface 54 a which is generallysemi-cylindrical with the same curvature as that of coping rail 24. Inaddition, a pair of side shelves 56 project out from deck wall 16 badjacent to the outboard ends of the notches 52. Shelves 56 are set infrom the opposite ends of wall 16 b enough to provide clearance of theupper ends of the front legs 14. Like shelf 54, shelves 56 havesemi-cylindrical upper surfaces 56a which are co-linear with surface 54a.

[0033] As shown in FIG. 3, the coping rail 24 is provided with a pair ofdownwardly extending tubular stubs 24 a which are sized and spaced apartto telescope into the upper ends of legs 14 when the coping rail isseated on shelves 54 and 56. When so seated, the is legs 14 may bereleasably secured to the coping rail 24 by spring-loaded push buttons58 projecting from rail stubs 24 a and which are adapted to snap intoholes 59 in legs 14.The washers 60 which sit on the upper end of legs 14support the front comers of deck 16 in the same manner of the washers 49over rear legs 12.

[0034] Preferably, as part of the initial set up of the quarter pipe,the coping rail 24 is permanently attached to shelves 54, 56 by suitablethreaded fasteners 62 (FIG. 3) inserted from below the shelves andthreaded into the rail. This leaves openings 64 between the rail and therear walls of notches 52 as shown in FIGS. 4 and 4A. Preferably also,the open ends of rail 24 are closed by suitable end plugs 70.

[0035] Referring to FIGS. 2 and 3, each ramp section 22 a has a curvedtop wall 72 a and a pair of opposite side walls 72 b and 72 c whichextend down from wall 72 a. As best seen in FIG. 2, a multiplicity ofribs 74 extend down from the underside of wall 72 a and form arectangular grid between the side walls 72 b and 72 c. Typically, eachsection is a molded article of the same material as base 10 and is about4 ft. long and 2 ft. wide. A series of wedge-shaped keys 76 project outfrom the side wall 72 b of each ramp section 22 a. These keys areadapted to key into a corresponding series of wedge-shaped keyholes 78in each ramp section wall 72 c to prevent movement of the two sectionsaway from one another, i.e. in a horizontal manner.

[0036] Referring to FIGS. 3, 4 and 6, a curved tongue 82 projects fromthe upper end of each ramp section 22 a. The tongue 82 is set in fromthe opposite sides of the ramp section and its length is slightly lessthan the length of the notches 52 in deck 16. The upper surface 82 a oftongue 82 has essentially the same curvature as the shelf surfaces 54 a,56 a. Thus after the coping rail 24 has been permanently anchored todeck 16 as described above, the ramp sections 22 a may be attached tothe deck by inserting the tongues 82 of the ramp sections into theopenings 64 behind rail 24 from below as shown in FIG. 4A and rotatingthe sections clockwise in that figure so that the tongue surfaces engageunder and behind rail 24 as shown in FIG. 4. Thus when the ramp sections22 a are in their downwardly sloping positions shown in FIG. 4, thetongues 82 of those sections are securely locked to deck 16. However,those connections still allow the sections to pivot about the rail tosome extent so that the legs 12, 14, on the one hand, and ramp entrysection 22 b, on the other, can rest stably on somewhat uneven ground.In other words, the connections allow automatic leveling of the quarterpipe on uneven ground. The connections also allow the ramp sections tobe detached from the deck 16 simply by swinging the sections 22 up tothe position shown in FIG. 4A and withdrawing the tongues 82 fromopenings 64; no tools are required for such detachment or subsequentreassembly.

[0037] As shown in FIGS. 1 and 3, in order to secure the lower end ofeach ramp section 22 a to entry section 22 b, the top wall 72 a of eachramp section is formed with a relatively large counter sunk hole 86having diametrically opposite, laterally extending notches 86 a in theedge of the hole. As will be described shortly, the hole 86 is adaptedto receive a locking cap 88 which locks the lower end of each rampsection 22 a to the entry section 22 b.

[0038] Referring now to FIGS. 3 and 5, entry section 22 b is preferablymade of the same material as base 10 and deck 16 and has more or lessthe same length and width dimensions as deck 16. The entry section has agently concavely curved top wall 92 a, a pair of opposite wedge-shapedsidewalls 92 b and 92 c, a rear wall 92 d and a bottom wall 92 e whichtogether define an internal fluid-tight cavity 94. As best seen in FIG.1, the entry section 22 b provides a sharp leading edge transition fromentry section 22 to the ground or other support surface.

[0039] An elongated key or lug 102 projects laterally from side wall 92b adjacent to the bottom of the entry section. Also, a key hole 104 isprovided in the opposite side wall 92 c of entry section 22 b which keyhole is arranged and adapted to receive the key 102 of an adjacentquarter pipe 8 so that two or more of the FIG. 1 quarter pipes 8 can beplaced side by side and locked together. In other words the key holes50, 78 and 104 of the quarter pipe 8 depicted in FIG. 1 are adapted toreceive the keys 48, 76 and 102 of the similar quarter pipe shown inphantom in FIG. 1. Thus, a series of quarter pipes may be lockedtogether to form a wider version of the quarter pipe shown in solidlines in FIG. 1.

[0040] Referring to FIGS. 3 and 5, the upper rear edge segment of entrysection 22 b is formed with a pair of laterally spaced apart shelves 110recessed or stepped down from the upper end of top wall 92 a, theshelves being separated by a vertical notch 112. Each shelf 110 has aninclined top wall with a discoid promontory 114 centered in the shelf.Furthermore, each promontory is formed with a relatively large lockinghole 116 centered in the promontory and which opens into cavity 94. Apair of diametrically opposite notches or keyholes 1 16a are present atthe edge of hole 116, the notches being aligned with the short axis ofthe entry section.

[0041] The entry section 22 b is designed so that when the lower endsegments of the ramp sections 22 a are seated side by side on shelves110, the opposing, keyed-together side walls 72 b and 72 c of the tworamp sections 22 a extend down into the notch 112 in entry section 22 band the holes 86 and notches 81 a of the two ramp sections are alignedwith the holes 116 and notches 116 a in the entry section promontories114. This allows each locking cap 88 to be inserted down through thecorresponding aligned holes 86 and 116. As best seen in FIG. 5, each cap88 includes a head 88 a, and a depending neck 88 b having at its freeend a pair of diametrically opposite keys or ears 88 c which are sizedto be received in the notches 86 a and 116 a when the ears are alignedwith the notches. Then by pressing down and turning the cap 88 about90°, the cap 88 firmly locks each ramp section 22 a to the entry section22 b as shown in FIGS. 1 and 5. Preferably, a pair of aligned slots 117are provided in each cap head 88 a so that the caps may be turned usingcoins inserted into the slots ; that is, no tools are required.

[0042] Referring to FIG. 5, like base 10, entry section 22 b, i.e. itscavity 94, may be filled with water, sand or the like by way of thelocking holes 116. Preferably, gaskets or seal rings 120 are provided onlocking caps 88 under their heads 88 a so that holes 116 are sealed whenthe locking caps 88 are locked in place as shown in FIGS. 1 and 5.

[0043] Referring to FIG. 6, all of the above-described components of theFIG. 1 quarter pipe 8 may be stacked and shipped along with a bag Bcontaining miscellaneous parts such as the end caps 40, fasteners 62,plugs 70, washers 49, 60, etc. in a relatively small volume package orcarton P. A customer may purchase the quarter pipe in that knock-downcondition and assemble it in a minimum amount of time, attaching thevarious components of the quarter pipe in the manner described above.After assembling the quarter pipe, the user may fill the base 10 and theentry section 22 b with a fluid to lower the unit's center of gravityand increase its mass so that the unit will not tilt or shift relativeto the ground when skaters, skateboarders and the like ride up and downthe quarter pipe 8. As noted above, a plurality of the quarter pipes 8can be connected together side by side in order to increase the overallwidth of the obstacle so that the children using the obstacle canperform more intricate acrobatic feats.

[0044] It will thus be seen that the objects set forth above among thosemade apparent from the preceding description, are efficiently attained.

[0045] Also, since certain changes may be made in the above constructionwithout departing from the scope of the invention, it is intended thatall matter contained in the above description or shown in theaccompanied drawings shall be interpreted as illustrative and not in alimiting sense.

[0046] It should also be understood that the following claims areintended to cover all of the generic and specific features of theinvention described herein.

What is claimed is:
 1. A knock-down quarter pipe for bikers,skateboarders and in-line skaters comprising pairs of upstanding frontand rear legs, said legs having lower ends lying in a common plane; adeck supported by said legs above said plane, said deck having front andrear edges; a rigid coping rail having opposite ends and extending alongthe front edge of the deck, directly above said pair of front legs;connections connecting said coping rail to said pair of front legs, anda ramp extending down from said front edge of the deck, said ramp havinga lower edge that is located in said plane and spaced in front of saidpair of front legs:
 2. The quarter pipe defined in claim 1 wherein thecoping rail comprises a cylindrical member and the deck and the ramphave upper surfaces which are generally tangent to the coping rail. 3.The quarter pipe defined in claim 2 and further including a hand railextending up from the deck adjacent to the rear edge thereof.
 4. Thequarter pipe defined in claim 1 wherein said ramp comprises an entrysection having a lower end which defines said lower leading edge and anupper end which defines a shelf; at least one arcuate ramp section eachsection having upper and lower ends and which extends from the copingrail down to said shelf, and a first securement for securing the upperend of the at least one ramp section so that it is adjacent and parallelto the coping rail.
 5. The quarter pipe defined in claim 4 wherein theramp includes first and second ramp sections situated side by side, anda second securement for securing the upper end of the second rampsection to the shelf.
 6. The quarter pipe defined in claim 7 wherein thedeck and entry sections each have corresponding first and second sidewalls, and connection means are present in the first and second sidewalls of the deck and entry sections enabling said quarter pipe to beconnected to an adjacent similar quarter pipe at the deck and entrysections of the two quarter pipes.
 7. A knock-down quarter pipecomprising a horizontal base; pairs of front and rear legs extending upfrom the base and for placement on a support surface below the base; adeck supported by the legs at a selected elevation above the base, saiddeck having an upper surface and a front edge defining a shelf thereatwhich is elevated above said pair of front legs; a rigid coping railseated on said shelf so that the rail is substantially level with saidupper surface of the deck, said rail having a pair of stubs extendingdown below said deck and being fastened to said pair of front legs; aramp having first and second ends and an upper surface extending betweensaid ends, and connections connecting the first end of the ramp adjacentand parallel to the front edge of the deck so that the second end of theramp is spaced in front of the base and rests on the support surface. 8.The quarter pipe defined in claim 7 wherein the ramp comprises two ormore similar ramp sections situated side by side, the first end of eachramp section being pivotally connected adjacent to the coping rail bysaid connections, and fasteners for fastening together adjacent ones ofsaid ramp sections.
 9. The quarter pipe defined in claim 7 wherein theramp comprises an entry section having a lower end which constitutessaid second end and an upper end which defines a shelf; at least onearcuate ramp section which extends from the front edge of the deck downto said shelf, and a securement for securing the at least one rampsection to the shelf.
 10. A knock-down quarter pipe for bikers,skateboarders and in-line skaters comprising a deck having a rear edge,a front edge defining a lateral trough therein and a surface extendingbetween said edges; a rigid grind rail seated in said trough so as to besubstantially level with said surface; a pair of front legs and a pairof rear legs extending down from the deck to a common plane, said pairof front legs having upper ends located directly under said grind rail;connections connecting said grind rail to said pair of front legs, and aramp having upper and lower ends and connected adjacent to the frontedge of the deck so that the upper end of the ramp is in front of andsubstantially parallel to said grind, rail and the lower end of the rampis spaced in front of said pair of front legs in said plane.
 11. Thequarter pipe defined in claim 10 wherein said ramp has an upper surfacedefining a concave arc.
 12. The quarter pipe defined in claim 10 whereinsaid grind rail is a cylindrical metal tube and the upper surfaces ofthe deck and ramp are generally tangent to the grind rail.
 13. Thequarter pipe defined in claim 10 and further including a base memberspaced below said deck and connecting said pairs of legs.
 14. Thequarter pipe defined in claim 10 wherein said ramp comprises an entrysection having a first end which defines said lower end of the ramp anda second end which defines a shelf; at least one ramp section whichextends from the front edge of the deck down to and overlies said shelf,and a securement for securing said at least one ramp section to saidshelf.
 15. The quarter pipe defined in claim 10 wherein said rampincludes first and second ramp sections situated side by side, and oneor more connections connecting said first and second ramp sections. 16.The quarter pipe defined in claim 10 and further including a hand railextending up from the deck adjacent to the rear edge thereof.
 17. Thequarter pipe defined in claim 1 and further including a first fluidvolume weighting down said base, and a second fluid volume weightingdown the lower end of said ramp.
 18. A knock-down quarter pipecomprising a platform assembly including a deck having an upper surfaceand a front edge defining a lateral trough therein, a rigid grind railseated in said trough so that the rail is substantially level with saidupper surface, means for anchoring the rail in the trough, and a pair offront legs and a pair of rear legs extending down from said deck to acommon plane, and a ramp assembly connected to said platform assembly,said ramp assembly including an entry section having a front enddefining a sharp edge lying in said common plane and a rear end defininga shelf, a first ramp section which extends from said deck down to saidshelf, said first ramp section having a lower end overlying said shelf,a second ramp section which extends from said deck down to said shelfnext to the first ramp section, said second ramp section having a lowerend overlying said shelf, and securements for securing the lower ends ofthe first and second ramp sections to said shelf.
 19. The quarter pipedefined in claim 1 and further including a base member spaced below saiddeck and connecting said pairs of legs.
 20. The quarter pipe defined inclaim 1 wherein said connections include a pair of stubs extending downfrom the coping rail below said deck and being fastened to the pair offront legs.
 21. The quarter pipe defined in claim 1 wherein said deckhas a trough at said front edge which is elevated above said pair offront legs; said coping rail is seated in said trough so that the copingrail is generally level with an upper surface of the deck, and saidconnections anchor the coping rail in said trough.
 22. The quarter pipedefined in claim 1 wherein said connectors include at least one notch inthe front edge of the deck, said notch being bridged by said copingrail, and a curved tongue extending from an upper end of the ramp, thecurvature of the tongue corresponding to that of the coping rail, saidtongue being shaped and dimensioned so that when said lower leading edgeof the ramp is elevated above said plane, the tongue may be insertedinto said at least one notch from below behind the coping rail so thatthe coping rail functions as a pivot for the tongue and when the lowerleading edge of the ramp is swung down to the level of said plane, thetongue becomes pivotally locked behind the coping rail.
 23. The quarterpipe defined in claim 22 wherein the coping rail has two depending stubsreleasably connected to the upper ends of the pairs of front legs. 24.The quarter pipe defined in claim 23 wherein the stubs aretelescopically received in the pair of front legs, and further includinglocking means for releasably locking the two stubs to the pair of frontlegs.
 25. The quarter pipe defined in claim 4 and further including aweight weighting down said entry section.